U.S. Pat. No. 5,609,759 and copending application Ser. No. 09/008,845, filed Jun. 20, 1998 (the disclosures of which are hereby incorporated by reference herein) illustrate and describe a very successful bottle mounted filter assembly primarily for significantly reducing the level of chlorine in tap water flowing through the filter out of the bottle. The carbon block filter element illustrated in the U.S. Pat. No. 5,609,759 patent also be used mounted at the bottom of a drinking straw disposed within a sport bottle, as is conventional. In both cases, however, since the filter is a radial flow filter, air can be ingested through the filter (aspirate) when the bottle is approaching empty, which results in an unpleasant gas filled issuance of water for as much as the last two to five ounces of the water being dispensed from the bottom (depending upon the bottle size). It is highly desirable to be able to eliminate or minimize the air being ingested through the filter so that substantially gas-free dispensing of water from the bottle may take place until right near the empty point.
According to the present invention a filter assembly is provided which significantly reduces, and in fact can substantially eliminate, the amount of air ingested through the filter for both cap mounted filters and straw mounted filters in conventional bottles with filters, such as shown in U.S. Pat. No. 5,609,759. This is accomplished, according to the invention, in a simple yet effective manner with a minimal addition cost in manufacture of the filter.
According to one aspect of the present invention a filter assembly is provided comprising the following components: A primarily radial flow filter element comprising a substantially prismatic or cylindrical body of filtering material having a first end through which filtered water flows, and a second end opposite the first end. A substantially tubular siphon shield (shroud) having cross-sectional interior dimensions greater than the exterior cross sectional dimensions of the filter element. A mounting element which mounts the siphon shield around the filter element so that there is a siphon space between the filter element and the siphon shield. And the siphon space cooperating with the siphon shield to significantly reduce the amount of air radially flowing through the filter element with water when parts of the filter element are uncovered by water. The siphon shield (or shroud) is normally independent of the filter and housing so that the shield may be retrofit onto existing filters, and may be removed from a filter and reoriented 180.degree. to change from a straw type filter to a cap type filter, and vice versa.
The filtering material of the radial flow filter element preferably comprises a hollow substantially continuous self-supporting, self-venting body of activated carbon and binder having a porosity of about 10-120 microns, and capable of reducing by at least 50% the amount of chlorine in water flowing through the filter at a flow rate of about 5 milliliters, such as disclosed in U.S. Pat. No. 5,609,759 and the copending application mentioned above, the disclosures of both of which have been incorporated by reference herein. However, other filter elements may also be utilized containing virtually any type of conventional technology, including ceramic filter elements, polymer extraction technology filter elements, iodinated resins, etc.
According to one embodiment of the invention, the filter element first end is operatively connected to a cap for closing the open end of a bottle, the cap having a manual valve (e.g. conventional push-pull valve, baby bottle nipples, etc.) associated therewith; and the mounting element mounts the siphon shield adjacent the second end of the filter element so that water can substantially only flow into the siphon space from adjacent the first end of the filter element, and wherein the siphon space is readily accessible to water adjacent the cap. The mounting element preferably comprises a mounting ring, and the siphon space is preferably substantially annular. For example, the substantially annular siphon space typically extends at least about 80% of the length of the filter element from the first end to the second end thereof, and typically at least about 90% of the effective filtering length of the filter element. For example, the siphon shield may comprise a substantially circular cross section substantially solid wall plastic tube and the filter element may be substantially cylindrical (and may be solid or hollow, preferably hollow), and the substantially annular siphon space has substantially uniform dimensions (that is the thickness of the annular space is approximately the same throughout the extent of the shield and filter element).
According to another aspect of the present invention, the filter element first end is operatively connected to a drinking straw; and the mounting element mounts the siphon shield adjacent the first end of the filter element so that water can substantially only flow into the siphon space from adjacent the second end of the filter element, and wherein the siphon space is readily accessible to water adjacent a bottom of a bottle in which the filter element and a portion of the drinking straw are disposed. The details of the mounted element, annulus, etc. for this embodiment are preferably as described above.
The siphon shield and the mounting element (e.g. mounting ring) are preferably integral and made of rigid plastic. The filter element may be "naked", that is uncovered by an accessory housing, or may be covered by an apertured decorative plastic housing, such as those sold by Innova Pure Water, Inc. as standard components of Innova "A" and "B" filters. The mounting element may be ultrasonically welded to the decorative housing, or attached by adhesive, or attached by adhesive directly to the external periphery of the carbon block filter element, or affixed by other known or conventional attachment techniques, such as a friction fit (which makes the shield removable).
According to another aspect of the present invention a filter assembly is provided comprising the following components: A primarily radial flow filter element comprising a substantially prismatic or cylindrical body of filtering material having a first end through which filtered water flows, and a second end opposite the first end. A substantially tubular solid shield having cross-sectional interior dimensions greater than the exterior cross sectional dimensions of the filter element. A mounting element which mounts the shield around the filter element so that there is a space between the filter element and the siphon shield. A cap for closing the open end of a bottle, the cap having a manual valve associated therewith. The filter element first end operatively connected to the cap wherein the mounting element mounts the shield adjacent the second end of the filter element so that water can substantially only flow into the space from adjacent the first end of the filter element, and wherein the space is readily accessible to water adjacent the cap. The mounting element may comprise a mounting ring, and the space may be a substantially annular siphon space, and the substantially annular siphon space may extend at least about 90% of the effective filtering length of the filter element. Other details of the components may be as described above.
According to another aspect of the present invention a filter assembly is provided comprising the following components: A primarily radial flow filter element comprising a substantially prismatic or cylindrical body of filtering material having a first end through which filtered water flows, and a second end opposite the first end. A substantially tubular shield having cross-sectional interior dimensions greater than the exterior cross sectional dimensions of the filter element. A mounting element which mounts the shield around the filter element so that there is a siphon space between the filter element and the shield. A drinking straw. The filter element first end operatively connected to the drinking straw. And wherein the mounting element mounts the shield adjacent the first end of the filter element so that water can substantially only flow into the siphon space from adjacent the second end of the filter element, and wherein the space is readily accessible to water adjacent a bottom of a bottle in which the filter element and a portion of the drinking straw are disposed. The filter element may extend axially outwardly from the shield adjacent the second end of the filter element so as to be sure to allow access to the substantially annular space between the filter element and the shield. The details of the components may be as described above.
Using the filter assemblies according to the present invention, whether with a squeeze bottle having a cap with a push-pull valve, or a sports bottle with a straw extending outwardly of the sports bottle cap, it is possible to effectively filter water yet minimize the amount of air ingested during the expelling or suction action by which the water is moved out of the bottle. In this way the amount of liquid that can effectively be removed from the bottle (without undesirable affects) is greatly enhanced compared to the prior art, with a minimum of additional costs or difficulty.